Generally, an automatic transmission serves to convert a power input into a torque converter to an appropriate transmission ratio by way of an epicyclic gear. In order to automatically form the appropriate transmission ratio, an operating device is equipped comprised of clutches and brakes for selectively activating an input element, an output element and a reaction element of the epicyclic gear. The operating device is controlled by a hydraulic control device and an electronic control device.
If a burning occurs at an operating element such as a clutch or a brake comprising an operating device of an automatic transmission, the epicyclic gear does not properly operate, resulting in an erratic transmission state. A worst case scenario that could occur in the epicyclic gear is an occurrence of an unwanted backward transmission state in the neutral or drive range.